Rather confused re water treatment!!!

[BenB]

I'm getting ready for my first AG mash. Only trouble is I'm confused to hell and back with water treatment (you wouldn't know I did A-level chemistry a couple of decades ago!!).... I know I could just try it a brew and see how it comes out but I'd rather do it properly the first time and (more importantly) understand what's going on!!! I've read the water treatment chapter in HTB about seven times now and am still none-the-wiser as TW refuse to give me Ca, Mg or alkalinity figures!!!
This is what I think I understand is going on:

Total hardness is a measure of Magnesium + Calcium including the hardness that doesn't boil out, and therefore isn't very useful as a figure (even though that's the only one that Thames Water are giving me).
Alkalinity is used as a measure of bicarbonates and carbonates.
Residual alkalinity is used to describe the effect whereby calcium and magnesium in the mash releases H+ from the grain to neutralise alkalinity in the mash.

So to know what your mash pH is going to be you need to somehow measure calcium, magnesium and alkalinity.

When you do the methyl orange test you're testing alkalinity (bicarb and carbonates) by virtue of the buffering effect of these compounds but then you still need to know Ca+Mg (or have estimates for them) to work out your residual alkalinity (and therefore mash pH and what treatments to use).

So- assuming this is correct, I can use an alkainity test kit to work out my bicarbs and carbs and providing I get a measure of Ca+Mg from TW (or cough up the £30 a private lab has quoted me to test PPM for bicarb, ca + mg from a water sample) I can work out what I need to do to the water to make my LP clone

Why I get confused is I can't help but feel that alkalinity and pH should be closely related. But I suppose the H+ content (pH) won't necessarily be ONLY offset by the alkalinity.... But if you're working out residual alkalinity from alkalinity and hardness won't initial water pH effect it?!?! Isn't this where I started?!?! Help!

[Aleman]

Chris is completely right, don't worry about water treatment for at least the first year or so of brewing

Why I get confused is I can't help but feel that alkalinity and pH should be closely related.

They are, sort of, as they are opposites of each other. pH is a measure of the Acidity (or concentration of H+ ions) of a liquid and alkalinity is a measure of the OH- (or HCO3-) Ions in a sample. In pure water the concentration of H+ is equal to the Concentration of OH- ions which is pH 7.0

[BenB]

Thanks for the answers!!!!

Aha. So it's the other bits in water (ie the bits which make it non pure) which create the gap between pH and alkalinity?
Cool. Makes sense!!!

So I'll measure the alkalinity (have you still got the kits Chris????? or do I need to go to the karp shop for the other test kits??) And bung in some gypsum. And add a campden to get rid of chlorides and chloramines and cross my fingers......

You'ld think that making a London beer with London water would be straightforward from a water point of view

[adm]

Ben,

I'm also in a Thames water area and had the same problem.

If you harass them, the bloke from the lab will call you up and give you a residual alkalinity figure. Mine was 108 mg/l CaCO3
They can also provide a Total Hardness number - mine was 145 mg/l CaCO3
Call customer services and tell them they are obliged to provide you these figures - they will eventually call you back.

I also bought a salifert TA test kit, and it says the TA is 134 mg/l - so i guess that's within possible error range of the water company figures. I use the kit number as it's a bang up to date measurement.

TW say they don't test for Calcium, but if you use Graham's water calculator it will make a stab at it from the numbers above - mine comes out as 58.06
It will also give you a number for Carbonate (CO3)

http://www.jimsbeerkit.co.uk/water/water.html

TW have numbers for Sulphate (SO4) and Chloride (Cl)

If you plug both of those numbers in, you'll have everything in the top row of the calculator apart from the Magnesium level.

But - assuming that the water in the pipe is balanced in cations and anions, then you can plug a figure into the magnesium box until the two numbers for the initial ion balance row are matched. In my case, 5 mg/l for Magnesium makes it all balance - and it's probably not far away from the truth.

[BenB]

Thanks for that info ADM, very useful!!!! I'm getting my head round this WT gig!!!

I've got a total hardness figure (from 2007 but hey....)

278.5 mgl CaCO3 (ppm)

It's the alkalinity I'm struggling with.... TW sent me an e-mail that said

"I have spoken to our Water Quality department and they have advised the
measurements in the water quality report show our statutory parameters. If any are not listed then we
are not regulated to sample for that parameter. "

which I think means "naff off" in customer services speak. But now I'll try again (and I've found the e-mail addy of the Customer services director which always helps)....

Am I right in thinking that a dash of gypsum as recommended will sort the pH (not need to crack open the lactic acid or find some wood ants to extract some muric acid from)....

[BenB]

Cool. I suspected it was buffering that was actually being discussed here..... It makes sense now. Remove the buffering and let the "bitter" malt bring down the pH.
Batch sparging is my way forward at this point- good to hear that the polyphenols will not be included... and hopefully with a London Pride brew as my first AG brew a few polyphenols (tannins etc) hopefully won't cause too much of an issue even if they creeped in there..
I just want to make sure that (hopefully) each time I smuggle the brew equipment into the house (my garage is full of cars, welders, superchargers, glass fibre dust and rats) I get a half decent brew out of it!!!! I probably won't get permission from the missus to have a bin bubbling away in the corner every day of the year so I better make sure the times I do count!!!!
Thanks for the advice!!!